What is a rooflight loft conversion?
A rooflight loft conversion (sometimes called a roof window conversion) keeps the existing roof shape and adds roof windows that sit flush with the slope. The floor is strengthened, a staircase is added and the space is insulated and finished.
How much does a rooflight loft conversion cost in Lancashire?
In Lancashire, a rooflight loft conversion typically costs £28,000–£42,500 for a typical rooflight conversion, including VAT at 20% (standard rate). The guide for Lancashire reflects typical costs in the North West, roughly 6% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £28,000–£42,500 |
| Higher specification | £42,500–£53,000 |
The biggest cost drivers are:
- Storage and finishes
- Staircase position
- Fire safety upgrades
- Bathroom or not
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a rooflight loft conversion in Lancashire?
Whether you need planning permission depends on your house and its location in England. In England roof windows are permitted development if they project no more than 15 centimetres from the roof slope and side-facing windows are obscure-glazed. Listed buildings need consent.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
We check this for your address before design work starts, so there are no surprises later.
What we handle
The work we manage on a rooflight loft conversion:
- Building control sign-off
- Drawings and structural calculations
- Roof windows installed
- Staircase and fire-safe escape route
- Head-height survey
- Insulation between and under rafters
How long does it take?
The build itself usually takes 4 to 6 weeks on site. Before that, surveys, drawings and approvals usually take 6 to 12 weeks, longer if the council asks for changes.
Building in Lancashire
Terraced streets across the North West often suit rear dormers and single-storey kitchen extensions.
Towns we cover in Lancashire include Preston, Burnley, Blackburn, Blackpool, Fylde and Rossendale.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about rooflight loft conversions in Lancashire
How much does a rooflight loft conversion cost in Lancashire?
In Lancashire, a rooflight loft conversion typically costs £28,000–£42,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Can I have a bathroom?
Yes, where there is enough head height at the shower or bath position.
How long does a rooflight loft conversion take in Lancashire?
Typically 4 to 6 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
What about fire safety?
The same escape rules apply as for any loft conversion, so a protected stairway and smoke alarms are typically needed.
Is it cheaper than a dormer?
Yes, usually, because the roof shape stays the same. But you gain less full-height floor space.